Problem: Simplify the following expression: $x = \dfrac{-r - 3}{r} \div \dfrac{1}{5}$
Explanation: Dividing by a number is the same as multiplying by its inverse. $x = \dfrac{-r - 3}{r} \times \dfrac{5}{1}$ When multiplying fractions, we multiply the numerators and the denominators. $x = \dfrac{(-r - 3) \times 5} {(r) \times 1}$ $x = \dfrac{-5r - 15}{r}$